Article stacking machine

ABSTRACT

An article stacking machine including a pair of continuously moving horizontally spaced vertically extending conveyors having a plurality of hingedly mounted article supports, a feeding conveyor for moving articles one at a time to a position above the vertically disposed conveyors and therebetween, a pair of pivotally mounted plate members for receiving the articles one at a time from the feeding conveyor and lowering the articles one at a time onto the article support members of the vertically disposed conveyors, a supporting structure between the vertically disposed conveyors and at the lower portion thereof for holding a stack base support member thereon during the stacking process, and an automatic pushing element for moving a formed stack from between the vertically disposed conveyors and simultaneously replacing the formed stack with an empty stack base support member while said vertically extending conveyors continuously receive articles and continuously move the articles toward the stack base support member.

United States Patent 91 Hiebert et al.

[ 1 Feb. 27, 1973 ARTICLE STACKING MACHINE [76] Inventors: Adoniram C.Hiebert, 3007 Innerdale Court, Randallstown, Md. 21133; Richard E.Lowry, 1823 Swansea Road, Baltimore, Md. 21214 [22] Filed: March 16,1971 [21] Appl. No.: 124,669

Related US. Application Data [63] Continuation-impart of Ser. No.821,234, May 2,

1969, abandoned.

[52] US. Cl ..214/6 FA, 198/158, 214/85 A,

214/8.5 F [51] Int. Cl ..B65g 57/14 [58] Field of Search ..214/6 DK, 6FA, 6 H, 6 P; 198/163,158,164

[56] References Cited UNITED STATES PATENTS 2,010,732 8/1935 Mandusic..214/6 FA X 3,458,058 7/1969 Faerber ..214/6 FA 2,919,821 l/1960 Young..214/6 FA 1,440,716 111923 Bliss ....214/6 FA X 2,669,342 2/1954 Neal..198/164 2,413,979 1/1947 Lamb ..214/6 FA 2,637,450 5/1953 Eshelman..214/6 FA Labombarde ..214/6 DK Primary Examiner-Robert J. SparAttorney-Oblon Fisher & Spivak [57] ABSTRACT An article stacking machineincluding a pair of continuously moving horizontally spaced verticallyextending conveyors having a plurality of hingedly mounted articlesupports, a feeding conveyor for moving articles one at a time to aposition above the vertically disposed conveyors and therebetween, apair of pivotally mounted plate members for receiving the articles oneat a time from the feeding conveyor and lowering the articles one at atime onto the article support members of the vertically disposedconveyors, a supporting structure between the vertically disposedconveyors and at the lower portion thereof for holding a stack basesupport member thereon during the stacking process, and an automaticpushing element for moving a formed stack from between the verticallydisposed conveyors and simultaneously replacing the formed stack with anempty stack base support member while said vertically extendingconveyors continuously receive articles and continuously move thearticles toward the stack base support member.

8 Claims, 18 Drawing Figures PATENTED FEB 2 7 I975 SHEEHOF 8 3.718.267

INVBNTOIS ADONIRAM C. HIEBERT RICHARD E. LDWRY BY 061011, Frk/mr 0! S amATTOR N EYS PATENTEUFEBZ'IIHYS SHEET 2 [If 8 FIG. 2

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ARTICLE STACKING MACHINE This application is a continuation-in-part ofcopending application Serial Number 821,234, filed May 2, 1969 to thesame inventors, now abandoned.

BACKGROUND OF THE INVENTION The present invention relates toimprovements in article stacking machines and, in one particular aspect,to a novel and improved stacking machine which is capable ofautomatically stacking a plurality of articles fed thereto byconventional conveying equipment and which is readily adaptable foraccommodating articles having diverse dimensional characteristics.

Modern manufacturing, processing and packaging techniques for thediverse and complicated products presently being produced and those tobe produced in the future have created a clear demand for theutilization of assembly line techniques and the birth of the age ofautomation. It has become increasingly more important to have modernautomatic equipment which utilizes a minimum amount of space and whichis capable of reducing the amount of personnel usually necessary forperforming such functions and which readily performs various functionsat high speed with good accuracy previously unattainable by the use ofpersonnel to perform the same or similar functions.

One of the major advanced made in the field of automation has been inthe development and manufacture of various types of machinery which hadthe capacity for automatically handling articles of manufacture duringthe various processing, packaging and shipping steps necessary for therapid and efficient production of articles of manufacture which arebeing produced at an increasingly rapid rate and in increasinglyenlarged quantities. To efficiently handle such articles of manufactureduring the processing, packaging and shipping procedures it has become avirtual necessity to stack and unstack raw materials, intermediateproducts, sheet materials, completed articles of manufacture, shippingcontainers, packages, and the like. Such stacking and unstackingprocedures have in the past been done largely as a manual step requiringthe constant attention of numerous employees whose time and effortscould be better used elsewhere. Furthermore, it is often impossible orimpracticable for said employees to devote sufficient time to stackingand unstacking procedures to do the work with any great amount ofprecision. Manual stacking and unstacking invariably results innon-uniform, crooked and unbalanced stacks. A further almost unavoidableresult of manual stacking and unstacking is the high incidence ofbreakage of the articles of manufacture.

Prior art machines and mechanisms have long been well known forperforming stacking and unstacking functions. Such prior art attemptshave achieved varying degrees of success, but none of the prior artattempts have been fully capable of satisfying the great variety ofneeds of modern material handling, in that they are generally designedto perform one specific function within a particular manufacturingprocess. Such machines have generally been limited to the han dling ofonly certain articles having the same dimensional and weightcharacteristics and have presented the further disadvantages of beingcomplex, cumbersome, difficult to assemble and dis-assemble, requirelarge amounts of valuable manufacturing space, have not been fullycapable of accurately forming stacks of uniform height and otherdimensional characteristics, and have been generally incapable ofhandling delicate materials, such as tile, slate, asphalt, ceramics, andthe like, without intolerable amounts of breakage. Many such prior artdevices are incapable of fully automatic operation, and althoughreducing the number of personnel necessary to perform the desiredstacking and unstacking functions, such machines have necessitated theuse of several employees to successfully operate when such employeescould much more fruitfully be utilized elsewhere. Many such prior artmachines have required separate machines or mechanisms of complexstructure and undesirably large size for feeding the articles to themachine and for discharging the articles from the machine. Virtuallynone of the prior art devices had in any way been adjustable so as toaccommodate various articles having diverse dimensional weightcharacteristics. One further disadvantage of those devices known to theprior art are that they generally require complex mechanisms and systemsfor the control thereof, which systems and mechanisms inevitablydecrease the reliability of the overall machines, increase theprobability of the machines breaking down, and increase the number ofhours necessary for ordinary maintenance and repairs. A still furtherdisadvantage of prior art devices is that it is necessary to run suchdevices intermittently to enable completed stacks to be removed thuscreating a general slowdown of the operation and increasing the chancesof a jam in the stacking operation.

SUMMARY OF THE INVENTION Accordingly, it is one of the objects of thepresent invention to provide novel and improved stacking and unstackingunits of low-cost manufacture which may be assembled with relative easein a minimum amount of space and which is capable of rapid and preciseoperation.

Another object of the invention is the provision of a new and improvedstacking machine which is capable of being adjusted to accommodatearticles of diverse dimensional characteristics.

It is a further object to provide a machine for automatically stacking aplurality of articles in a smooth and continuous manner such that thearticles are not damaged during the stacking operation.

Still a further object of the present invention is the provision of anew and improved machine for automatically and continuously stacking aplurality of articles which is capable of receiving the articles from aconventional conveying system, forming a stack of the articles andautomatically replacing a stack of the desired height with an emptystack base supporting member without the assistance of an operator.

By way of a summary account of practice of this invention in one of itsaspects, a machine for automatically stacking a plurality of articles isprovided with a pair of continuously moving horizontally spacedvertically extending conveyors, a driving mechanism for simultaneouslymoving the conveyors at the same velocity, a support for the stack basemember positioned between the conveyors at the lower portion thereof, amechanism for continuously feeding the articles one at a time to aposition above the conveyors,

and a mechanism for receiving the articles from the feeding mechanismand for lowering the articles onto the conveyors.

BRIEF DESCRIPTION OF THE DRAWINGS Although the features of thisinvention which were considered to be novel are set forth in theappended claims, further details as to preferred practices as to thefurther objects and features thereof may be most readily comprehended toreference to the following description taken in connection with theaccompanying drawings, wherein:

FIG. 1 is a perspective view in schematic form, with parts not shown,illustrating the operative steps of the stacking machine of the presentinvention;

FIG. 2 is a plan sectional view, with parts not shown, in schematic formillustrating the back portion of the stacking machine of the presentinvention;

FIG. 3 is a plan view, with parts not shown, illustrating the drivemechanism for the conveyors of the stacking machine of the presentinvention;

FIG. 4 is a plan side view, with parts cut away, illustrating a portionof the functional elements of the stacking machine of the presentinvention;

FIG. 5 is an exploded view of the conveyor and article support;

FIG. 6 is an exploded top plan view of the conveyor elements of FIG. 5;

FIG. 7 is a top plan view, with parts broken away, of the stackingmachine of the present invention;

FIG. 8 is an exploded sectional view taken along the lines 8-8 ofFIG. 7;

FIG. 9 is a top plan view, with parts broken away, illustrating theoperating mechanism for the article lowering device;

FIG. 10 is a partial sectional view taken along the line 10-10 ofFIG. 9;

FIG. 11 is a partial sectional view similar to FIG. 10 with theoperating mechanism in a second position;

FIG. 12 is a schematic view of the fluid operating mechanisms associatedwith the present invention;

FIG. 13 is a schematic perspective view of the unstacking machine of thepresent invention;

FIG. 14 is a schematic view, with parts broken away, of an operativestep of the stacking machine of FIG. 1;

FIG. 15 is a schematic view, with parts broken away, of an operativestep of the stacking machine of FIG. 1;

FIG. 16A is a schematic view of a first operative step of the stackingmachine,

FIG. 16B is a schematic view of a second operative step of the stackingmachine; and

FIG. 16C is a schematic view of a third operative step of the stackingmachine of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawingswherein like reference characters designate identical or correspondingparts throughout the several views, and more particularly in FIG. 1thereof wherein is shown in a schematic manner the article stackingmachine of the present invention with the stacking portion of themachine indicated generally by the reference numeral 10. The entiremachine structure is supported by conventional frame members, such forexample as I-beams, U-beams, angle irons, and the like. Coveringmaterials of plywood, sheet metal, and the like, such as illustrated at12, may be utilized, without interfering with the functional operationof the article stacking machine of the present invention.

The articles 14 to be stacked are conveyed by a con ventional conveyingmechanism 16 to a position above the stacking structure 10. The feedingconveyor structure 16 in one illustrative embodiment includes aplurality of rollers 18 which are driven by a belt-type conveyor, notshown on the top or underside surface thereof in conventional manner.The articles 14 when positioned above the structure 10 are lowered intothe mechanism by a device to be more fully described hereinafter. A pairof conveyors 20 and 22 having article supporting members 24 hingedlymounted thereto are provided for moving the articles one at a time in adownward direction until such articles come to rest upon the top of thestack being formed therebelow. A stack base supporting member 26 isprovided between the conveyors 20 and 22 at the lower portion thereoffor receiving the articles being conveyed downwardly, such that thestack is formed atop the base member 26. Obviously, if the articles areof sufficient strength and rigidity, the base members 26 can beeliminated. A conventional conveying mechanism 28, of similar structureto the conveying mechanism 16 is provided for moving a plurality ofstack supporting base members 26 to a position adjacent the stackingdevice 10. When the stack has reached a pre-selected desired height, afluid operated pushing element 30 of the piston-cylinder type moves anempty base supporting member 26 between the conveyors 20 and 24 andsimultaneously moves the completed stack to the rear of the stackingmechanism by means of a plurality of rollers 32. Any conventionalmechanism, such as a solenoid operated switch, a photo-electric cell,and the like, may be utilized for detecting when the stack has beencompleted for actuating the pusher element 30. The completed stacks maybe transferred by conventional conveying mechanisms to further stationsto be processed, packaged, shipped, or stored. As can be easily seenfrom reviewing the schematic representation in FIG. 1, the entireoperation of the stacking machine is fully automatic and does notrequire the valuable time and efforts of employees. It is to be furthernoted that the stacking operation is completely versatile and may bereadily assembled in a minimum amount of space at virtually any locationwithin the manufacturing facilities.

Referring now to FIGS. 2, 3 and 4, the horizontally spaced verticallyextending conveyors 20 and 22 are illustrated as each including a pairof spaced closed loop chains 34 which form a continuous pad and whereineach of the chains 34 is constructed of a plurality of flexiblyinterconnected lengths 36 of conventional construction. A pair of upperhorizontally extending shafts 38 are each provided with a pair of piniongears 40 which are in driving engagement with the chains 34. A pair oflower horizontally extending shafts 42 are similarly provided with apair of pinion gears 44 which are in driving engagement with the lowerportions of the chains 34. Each of the shafts 38 and 42 are mounted inconventional bearing structures 46 for rotation therein. Extendingbetween the corresponding chains 34 of each of the conveyors 20 and 22are the article supporting members 24 which preferably are evenly spacedabout the entire outer surface of the chains 34. As more clearly seen inFIGS. 4 and 5, the sprockets or pinions 40 are driven in acounter-rotating manner at the same velocity by means of a driving motor48. Gears 50, on the forward terminal portion of shafts 38 are engagedby a sprocket chain 52 which is driven by loader 48. The chain engagesgear 50 associated with conveyor 22 at the outer portion thereof andengages gear 50 associated with conveyor 20 at the inner portion thereofsuch that the inner flights of the conveyors will both move in adownward direction at the same velocity. An idler gear 54 is provided onan adjustable tightening bracket 56 for maintaining chain 52 in theposition shown in FIG. 3. Bracket 56 may be adjusted by means of bolt 58extending through a slot 60 therein such that the chain 52 is maintainedin a taut condition.

As more clearly shown in FIGS. 4, 5 and 6, the article supportingmembers 24 are secured to one leaf 62 of a hinge by conventional means,such as welding. The other leaf 64 of the hinge is secured to a link 36of the chain 34 through a bracket 66 by conventional means, such as bolt68. Leaves 62 and 64 are rotatably by means of binge pin 70 in theconventional manner. A stop member 72 is secured to leaf 64 byconventional means, such as welding such that leaf 62 is maintained in ahorizontal position during at least a portion of the downward movementof chain 34. Since leaf 62 engages stop 72 to be maintained in ahorizontal position, it can readily be seen that the article supportmembers 24 will likewise be maintained in a horizontal position duringthe same portion of the flight of the conveyor. Stop 72 further acts asa stack alignment guide since it will engage an article therebelow topush the article in alignment with the stack should the article havemoved out of position.

A turnover mechanism 80 in the form of a wheel is secured to the centralportion of shafts 38, as shown in FIGS. 7 and 8, for assuring thatsupport members 24 are maintained in the horizontal position during theupper portion of the downward flight of the conveyors. With an articlesupported between the conveyors 20 and 22 and resting on correspondingsupport members 24, the article will be lowered to a position wherein itengages the top of the stack being formed at the lower portion of theconveyors. At such time as the a:ticle engages the stack being formed,article support members 24 will likewise engage the top of the stack andwill be pivoted upwardly to a substantially vertical position such thatthe article will come to rest atop the stack as the article supportmembers continue downwardly. The article support members 24 will beretained in the vertical position during the remainder of the downwardflight of the conveyors by the engagement with the formed stack, andwill likewise be maintained in a substantially vertical position duringthe upward portion of the flight of the conveyors due to gravity. Uponreaching the top of the upward portion of the flight of the conveyors itis highly desirable to re-position the article support members in thehorizontal position such that they are capable of receiving anotherarticle to be conveyed downwardly to the top of the stack. A leg member82 formed integrally with the article support members 24 and extendingperpendicularly therefrom is provided for cooperation with wheel at thetop of the conveyors 20 and 22 such that the leg member 82 will engagewheel 80 at the top of the upper flight of the conveyors which in turncauses the article support member 24 and integrally formed leg member 82to rotate about pin 70 until the article support member 24 has come tothe horizontal position, as shown in FIG. 8.

In order to expeditiously transfer the articles to be stacked from thefeeding conveyor 16 onto the article supporting members on the conveyors20 and 22 in a manner which does not cause excess wear or breakage tothe articles, a horizontal support is provided above the conveyors whichis pivotally mounted for lowering the articles onto the articlesupports. As was clearly seen in FIGS, 4, 7, 9, l0 and 11, thehorizontal support consists of a pair of spaced plate members which arefixedly secured to shafts 92 by an offset bracket 94 of generallyZ-shape in a conventional manner, such as by welding. Shafts 92 aremounted at their terminal portions in bearing members 96 for rotationtherein. It is necessary to maintain the plate members 90 in thehorizontal position shown in FIG. 4, during the period when an articleis being conveyed onto the plate members 90 by conveyor 16. Once anarticle is in position on the plate members 90 it is then necessary todownwardly rotate the plate members in a controlled manner such that thearticle supported thereon will be lowered between the conveyors 20 and22 to be deposited upon the uppermost set of article supporting members24. As seen most clearly in FIGS. 9, l0 and 11 an actuation such as adouble piston-cylinder arrangement 98 having piston extensions 100projecting therefrom provides a fluid operated mechanism for maintainingthe plate members 90 in a horizontal position while being loaded and forslowly rotating the plate members in a downward direction.Interconnecting shaft 92 and piston rod 100 is a linkage arrangementincluding a rod member 102 pivotally mounted to a link 104 through a pinmember 106, thus, it can be seen that when fluid has been evacuated fromthe piston-cylinder arrangement through conduits 108 the piston rod 100will be extended thus rotating shaft member 92 to the position shown inFIG. 10 wherein the plate members 90 will in a substantially verticalposition. Upon the application of fluid pressure to conduits 108, thepistons will receive within the cylinders 98 such that piston rod 100will be moved to the position shown in FIG. 11, thus rotating shafts 92through an angle of approximately 90 which will therefore, orient theplate members in a substantially horizontal position.

With the plate members 90 in a fixed position there are obviouslycertain limitations as to the ability for the plate members to handlearticles of varying diverse dimensions. Therefore, a pair of brackets110 are fixedly secured to the framework of the stacking machine suchthat bearings 96 are mounted within slots 112 by means of conventionalsecuring elements, such as bolts 114, as clearly shown in FIGS. 7 and 9.In this manner, it can readily be seen that at least one of the platemembers 90 is adjustable relative to the other plate member by slidinglyadjusting the bearing elements 96 within the slots 112 of brackets 110such that the plate members are enabled to accommodate articles ofvarying diverse dimensional characteristics. It is likewise desirable tohave the capacity for adjusting the spacing between conveyors 20 and 22such that the article supporting members 24 will have the capacity tosupport articles of diverse dimensional characteristics. A pair ofbrackets 120 are provided at the upper portion of the stacking machineand a corresponding pair of brackets 122 are mounted at the lowerportion of the stacking machine, each being of similar design such thatthe bearing members 46 supporting one of the conveyors, conveyor 20 asshown in the drawings, for movement relative to the other of theconveyors. The bearing structures are mounted to bracket members 120 and122 by means of a slot 124 formed within the bracket members throughwhich conventional securing members, such as bolts 126 may be attached.It is to be understood that when plate members 90 are to be adjustedrelative to each other it is necessary to adjust or replace connectingarms 102 with either a larger or smaller connecting element which willadequately suit the purpose.

Referring now to FIG. 12, wherein an exemplary fluid operating system isillustrated in a schematic manner, the piston-cylinder arrangement 30for removing a completed stack as well as the piston-cylinderarrangements 98 for operating the plate members 90 are illustrated as ina common fluid operated system. A constant fluid source 130 communicateswith a pair of conduits 132 and 134 to introduce fluid pressure, such apneumatic or hydraulic pressure to a pair of valve members 136 and 138,each of which may be operated by conventional mechanisms, such assolenoids. Valve member 136 would be considered of conventional designsuch that in a first position fluid pressure would be introduced throughconduit 132 into valve 136 to be distributed into conduits 108 forretracting the pistons within the cylinders 98 to raise the platemembers 90 to a horizontal position. In the second position of valve 136fluid would be exhausted to conduits 108 and pressure vented throughconduit 109 thus permitting the plate members 90 to retract to thevertical position. Fluid entering into valve 138 through conduit 134would be directed to conduit 140 in a first position of the valve toretract the piston I42 and in the second position of valve I38 fluidpressure would be directed to conduit 144 to activate the pushingelement 142 such that the pallet 26 would be pushed into the stackingmachine or when pallet 26 is not used, the stack would be removed. Thecontinuous operation of the stacking machine of the present invention ismost clearly described with reference to FIGS. 14-16. A switch 301, ofconventional design, is positioned above the plate members 90 adjacentthe far side thereof so as to be activated by an incoming article 14when the article is in the proper position to be stacked. A secondswitch 302 is positioned outwardly of one of the vertical conveyors 20or 22 so as to be activated by a supporting member 24 which wouldindicate that the supporting member 24 at the top of the downward flightof the conveyors would be in the proper position 304 for receiving anarticle 14 to be stacked. Once switch 302 has been triggered, the platemembers 90 would move to the downward position to deposit the article 14onto the supporting members 24 when in the proper position 304. Theposition of switch 302 is adjustable such that thepoint atwhich theplates 90 deposit the article on the material handler can be varied. Aswitch 303 is positioned adjacent the conveyor 22 between the upward anddownward flight thereof at an elevation to indicate the top of acompleted stack. As the last article 14 to be deposited on the top ofthe stack begins to come to rest upon the stack, the article supportingmembers at the sides thereof are swung backward so as to trip the switch303 indicating the completion of the stack. The shortest possible time Tbetween the triggering of switch 303 and the arrival of the next productto the top of the stack would beequal to the distance D between thearticle support members 24 divided by the speed of the conveyors 20 and22 carrying the article support members.

article members Speed of conveyors carrying article support membersD-the thickness of the article V V In time T, a stack having a width W,as shown in FIG. 16, must be out of the way of the article at point 304.Assuming the rate of travel of the pushing element to be equal to V butT, (Dt)/V such that V WV/(Dt). Switch 303 would operate a solenoid valveto actuate the pushing element 142. It can be seen that by properlypositioning the switches 302 and 303 a completed stack can be removedfrom the stacking machine without interrupting the motion of theconveyors 20 and 22 or the plate members 90.

The same basic structure utilized for the stacking operations is alsoused for unstacking a loaded pallet with some basic modifications.Referring to FIG. 13, the unstacking machine indicated generally by thenumeral 200 isof the same basic construction as the stacking machine 10illustrated in FIG. 1 and those parts of the same or similar structureare therefore not described with relationship to the unstacking machine.For example, conveyors 202 and 204 in the stacking machine and theassociated driving mechanisms would be basically the same as conveyors20 and 22. in the stacking machine 10. In the stacking machine 200 it isto be noted that a plurality of stacks 206 are fed into the stackingmachine by conventional conveying equipment 208 and a pushing element ofsimilar construction as the conveying mechanism 28 and pushing element30 of the stacking machine. The direction of the conveyors 202 and 204are such that the inner portions of the conveyors form an upwardlymoving flight of the conveyors. Article support members 212 are fixedlysecured to the conveyor elements in that a hinge mounting is notnecessary for the unstacking operations. It is to be further noted thatonly two sets of article supporting members 212 are utilized in theunstacking machine and the sets are located 180 out of phase. Additionalsets of article supporting members can be utilized depending upon theheight of the stacks to be formed and the height of the overall stackingmachine. As the stack 206 reaches the upper portion of the conveyorelements a conventional piston-cylinder type pushing element 214 isutilized in a reciprocating manner to discharge the articles 216 one ata time onto a roller type conveyor of conventional construction asillustrated at 218 in the drawing. Once all of the articles 216 havebeen discharged from the stack a second pushing element of conventionalconstruction such as illustrated at 220 in the drawing may be utilizedfor discharging the pallets or stack supporting members onto a dischargeconveyor 222. It is to be noted that any conventional dischargingmembers could be utilized with the unstacking machine of the presentinvention, and is not intended that the invention be limited to pistontype discharging elements. It can therefore be seen that in both thestacking and unstacking operations the machine of the present inventionprovides a compact, efficient, highly versatile component which may beintroduced into a manufacturing plant for performing various stackingand unstacking functions. It is further to be noted that such stackingand unstacking operations performed by the machine of the presentinvention can be utilized in combination with various other types ofmechanisms for combining a plurality of similar articles into acomposite structure with the assistance of conventional equipment suchfor example as stapling apparatus, glue, gluing apparatus and the like.

Obviously, numerous modifications and variations of the presentinvention are possible in light of the above teachings. It is thereforeto be understood that within the scope of the appended claims theinvention may be practiced otherwise than as specifically describedherein.

What is claimed as new and desired to be secured by Letters Patent ofthe United States is:

1 A machine for automatically stacking a plurality of articlescomprising:

a pair of horizontally spaced vertically extending conveyors eachcomprising a pair of spaced closed loop chains forming a continuous pathand constructed of a plurality of flexibly interconnected lengths, upperand lower horizontally extending shafts each having a pair of piniongears in driving engagement with said chains, a plurality of spacedhinges having one leaf of each hinge secured to one of said chains andthe other leaf thereof free to move relative to said securing leafthrough an are greater than 90, a plurality of article supportingmembers extending between said chains and secured to the free leaves ofa pair of corresponding horizontally aligned hinges on said chains, andstop means secured to the fixed leaf of said hinge for retaining saidfree leaf and attached article supporting member in a horizontalposition during at least a portion of the downward flight of saidconveyors;

means for continuously moving said conveyors simultaneously at the samevelocity;

means for supporting a stack base member between said conveyors at thelower portion thereof;

means for feeding said articles one at a time to a position above saidconveyors;

mean for receiving said articles one at a time from said feeding meansand for lowering said articles onto said conveyors such that saidvertically extending conveyors continuously move said articles towardsaid stack base member;

means for automatically removing said stack base member from betweensaid conveyors when a stack of desired height has been formed thereonand for simultaneously positioning an empty stack base member betweensaid conveyors in place thereof while said vertically extendingconveyors continuously receive said articles and continuously move saidarticles toward said stack base member;

means for positioning said article supporting members in a horizontalposition at the upper portion of said downward flight of said conveyors;

a leg member integral with and extending from said article supportingmembers, and wherein said positioning means comprises at least onemember affixed to said upper shaft for engagement with said leg members.

2. A machine as set forth in claim 1 wherein said means for receivingsaid articles from said feeding means and for lowering said articlesonto said conveyors comprises:

means for providing a horizontal support for said articles above saidconveyors; and

means for pivoting said horizontal support means downwardly between saidconveyors.

3. A machine as set forth in claim 2 wherein said pivoting meanscomprises at least one shaft member affixed to at least one segment ofsaid horizontal support means, said shaft member being mounted forrotation within bearing means, and

means for rotating said shaft member.

4. A machine as set forth in claim 2 wherein said horizontal supportmeans comprises a pair of spaced plate members, and wherein saidpivoting means coinprises a pair of shaft members each affixed to one ofsaid plate members, said shaft members being mounted for rotation withinbearing means, and

means for rotating said shaft members.

5. A machines as set forth in claim 4 wherein said shaft members affixedto said plate members are per"- pendicular to said horizontallyextending shafts of said conveyors.

6. A machine as set forth claim 4 wherein at least one of said pivotingshaft members is adjustably supported so as to be adjusted toward andaway from the other of said pivoting shaft members, whereby saidhorizontal support means is readily adaptable for various size articles.

7. A machine as set forth in claim 3 wherein said means for rotatingsaid shaft member includes a fluid operated piston-cylinder mechanism,and

means for linking said piston with said shaft member.

8. A machine as set forth in claim 4 wherein said means for rotatingsaid shaft members includes a pair of fluid operated piston-cylindermechanisms, and

means for linking each of said pistons with a corresponding shaftmember.

1. A machine for automatically stacking a plurality of articlescomprising: a pair of horizontally spaced vertically extending conveyorseach comprising a pair of spaced closed loop chains forming a continuouspath and constructed of a plurality of flexibly interconnected lengths,upper and lower horizontally extending shafts each having a pair ofpinion gears in driving engagement with said chains, a plurality ofspaced hinges having one leaf of each hinge secured to one of saidchains and the other leaf thereof free to move relative to said securingleaf through an arc greater than 90* , a plurality of article supportingmembers extending between said chains and secured to the free leaves ofa pair of corresponding horizontally aligned hinges on said chains, andstop means secured to the fixed leaf of said hinge for retaining saidfree leaf and attached article supporting member in a horizontalposition during at least a portion of the downward flight of saidconveyors; means for continuously moving said conveyors simultaneouslyat the same velocity; means for supporting a stack base member betweensaid conveyors at the lower portion thereof; means for feeding saidarticles one at a time to a position above said conveyors; mean forreceiving said articles one at a time from said feeding means and forlowering said articles onto said conveyors such that said verticallyextending conveyors continuously move said articles toward said stackbase member; means for automatically removing said stack base memberfrom between said conveyors when a stack of desired height haS beenformed thereon and for simultaneously positioning an empty stack basemember between said conveyors in place thereof while said verticallyextending conveyors continuously receive said articles and continuouslymove said articles toward said stack base member; means for positioningsaid article supporting members in a horizontal position at the upperportion of said downward flight of said conveyors; a leg member integralwith and extending from said article supporting members, and whereinsaid positioning means comprises at least one member affixed to saidupper shaft for engagement with said leg members.
 2. A machine as setforth in claim 1 wherein said means for receiving said articles fromsaid feeding means and for lowering said articles onto said conveyorscomprises: means for providing a horizontal support for said articlesabove said conveyors; and means for pivoting said horizontal supportmeans downwardly between said conveyors.
 3. A machine as set forth inclaim 2 wherein said pivoting means comprises at least one shaft memberaffixed to at least one segment of said horizontal support means, saidshaft member being mounted for rotation within bearing means, and meansfor rotating said shaft member.
 4. A machine as set forth in claim 2wherein said horizontal support means comprises a pair of spaced platemembers, and wherein said pivoting means comprises a pair of shaftmembers each affixed to one of said plate members, said shaft membersbeing mounted for rotation within bearing means, and means for rotatingsaid shaft members.
 5. A machines as set forth in claim 4 wherein saidshaft members affixed to said plate members are perpendicular to saidhorizontally extending shafts of said conveyors.
 6. A machine as setforth claim 4 wherein at least one of said pivoting shaft members isadjustably supported so as to be adjusted toward and away from the otherof said pivoting shaft members, whereby said horizontal support means isreadily adaptable for various size articles.
 7. A machine as set forthin claim 3 wherein said means for rotating said shaft member includes afluid operated piston-cylinder mechanism, and means for linking saidpiston with said shaft member.
 8. A machine as set forth in claim 4wherein said means for rotating said shaft members includes a pair offluid operated piston-cylinder mechanisms, and means for linking each ofsaid pistons with a corresponding shaft member.